Utilizing Endocytic Dynamics to Obtain Comprehensive Spatiotemporal Tension Maps of Live Tissues Project Summary Tension in tissues relates to pivotal morphological changes during development, as well as pathologic transformations that trigger cardiovascular disorders and cancer metastasis. Prevalent techniques employed to quantify cellular tension are not applicable to tissues due to their invasive nature. This technical gap is a critical barrier for biomedical research aiming to elucidate the roles of tissue mechanics in disease progression and developmental disorders. We propose developing a methodology for quantifying the tensile forces within cells and tissues by characterizing the tension response of a major cellular membrane traffic pathway: clathrin-mediated endocytosis (CME). Our previous works and precursor experiments show that spatial and temporal variations in tension can be determined through the analysis of CME dynamics in cells. We propose that the robust anticorrelation between tension and CME dynamics can be used to develop comprehensive spatiotemporal tension maps of living systems noninvasively. In Aim 1, we will characterize the parameters defining CME dynamics at distinct values of cell tension. We will also determine the spatial and temporal resolving power of tension maps developed using CME dynamics. In Aim 2, we will validate the applicability of the proposed methodology to tissues of living multicellular organisms. We will use Drosophila melanogaster embryogenesis as the model developing organism. In Aim 3, we will develop a software platform for generating tension maps by utilizing CME dynamics. We envision that this high-risk, high-payoff approach will provide a major leap in biomedical research as it offers noninvasive assembly of comprehensive spatiotemporal tension maps of tissues using broadly available fluorescence imaging modalities.